|President of the High Court|
1 August 1995 – 12 October 1998
|Appointed by||Mary Robinson|
|Preceded by||Harry Whelehan|
|Succeeded by||Frederick Morris|
|Judge of the High Court|
1 June 1977 – 3 September 1998
|Appointed by||Patrick Hillery|
|16th Attorney General of Ireland|
15 March 1973 – 19 May 1977
|Preceded by||Colm Condon|
|Succeeded by||John M. Kelly|
February 1973 – June 1977
May 1951 – June 1969
|Born||Declan John Costello|
1 August 1926
Fairview, Dublin, Ireland
|Died||6 June 2011 (aged 84)|
Beaumont Medical Clinic, Dublin, Ireland
|Resting place||Shanganagh Cemetery,|
Shankill, Dublin, Ireland
|Political party||Fine Gael|
(m. 1954; d. 2011)
|Alma mater||University College Dublin|
Declan Costello (1 August 1926 – 6 June 2011) was an Irish judge, barrister and Fine Gael politician who served as President of the High Court from 1995 to 1998, Judge of the High Court from 1977 to 1998 and Attorney General of Ireland from 1973 to 1977. He served as a Teachta Dála (TD) for the Dublin North-West constituency from 1951 to 1969 and for the Dublin South-West constituency from 1973 to 1977.
Costello was born in Dublin, the son of John A. Costello who served as Taoiseach on two occasions. He was educated at University College Dublin (UCD), and was an auditor of the UCD Law Society. At the 1951 general election he was elected to Dáil Éireann as a Fine Gael Teachta Dála for the Dublin North-West constituency and was re-elected at every subsequent election until he stood down at the 1969 general election. He stood again in the Dublin South-West constituency at the 1973 general election, and was elected for a final time, to the 20th Dáil.
During the 1960s Fine Gael was out of power and Costello was leader of a new generation of Fine Gael politicians who wanted to move the party to the left. He persuaded the party to publish a document called Towards a Just Society, which supported economic planning and more government intervention in the economy. This document went on to define what Fine Gael stood for over the following twenty years.
When Fine Gael returned to government in 1973, Costello was appointed Attorney General under Taoiseach Liam Cosgrave. He served in that position until 1977, when he finally left politics to become a Judge of the High Court. In 1979 he presided over the Costello Inquiry into the Whiddy Island Disaster. He was appointed President of the High Court in 1994 and retired in 1997. Costello died in 2011.
| Attorney General of Ireland
| President of the High Court